Electrical connector



Patented May 97,

ELECTRICAL CONNECTOR Edwin A. Noyes, Chevy Chase, Md., assigner of twenty-five per cent to Stewart K. Brown, Alexandria, and twenty-five per cent to Frank G. Campbell, Arlington County, Va.

Application August 5, 1947, Serial No. 766,298

2 Claims.

This invention relates to electrical connectors and it has for its object to provide a device of this character adapted to make electrical connection with a screwhead or like device, in such manner that secure attachment of the connector to the screw head may be eiected and considerable pressure may be exerted between the connector and the screwhead.

The device is primarily intended for use in testing and servicing watt-hour meters under conditions hereinafter set forth.'

The invention will be best understood by refer ence to the accompanying drawing wherein;

Fig. 1 is a front elevation of a standard and Well-known meter test block used in connection with the mounting and testing of watt-hour meters.

Fig. 2 is a vertical sectional View upon line 2 2 of Fig. 1 looking in the direction of the arrow.

Fig. 3 is a sectional view illustrating a modifiedform of screw, with which the device of the invention is adapted to make connection.

Fig. 4 is a sectional view upon line 4 4 of Fig. 6.

Fig. 5 is a transverse sectional view upon line 5 5 of Fig. 2.

Fig. 6 is a plan view of the connector of the invention.

Fig. 7 is a side elevation of one of the connectors showing a protecting insulating sleeve applied to the exterior thereof; and

Fig. 8 is a longitudinal sectional view of a modified form of the invention.

Like numerals designate corresponding parts in all of the gures of the drawings. The advantages of the invention will be best understood by first considering the conditions which have brought about its development. The conventional watt-hour meters commonly employed for measuring the current delivered to the customers of electric power companies must be tested or possibly repaired -from time to time. When that is to be done they are removed from their mounting and in order that the service to the customer may not be interrupted during the time that the meter is removed, it has been the practice and is now the practice to utilize short sections of cable with spring clips upon their ends to constitute jumpers by which the connections to the meter may be bridged and the service continued until the meter can be replaced.

To facilitate the testing operation the meters (not shown) are mounted in metal boxes (not shown), and'in these boxes and below the meters are mounted meter test blocks such as the one illustrated in Fig. l. These test blocks are made of hard rubber or other insulating material and they comprise a rear wall 5 and a plurality of fore and aft partition walls 6. The electric cables which conduct the current to and from the meter are indicated at l, 8, 9 and In. The bared ends I I of these cables are bound by screws I2 against the rear walls I3 of heavy copper or other metallic sleeves I4, said screws I2 being threaded into the front walls, I5, of these sleeves. Said sleeves are received in the pockets I5, said pockets being bounded by the division walls E upon their sides, the rear wall 5 at their rear sides and .a trans verse front wall at Il. Connecting straps I8, I9, 20 and 2l which lead downwardly from the meter (not shown) are connected to the sleeves I4 by binding screws 22. Thus, with the meter in place, the connection will be from cable Iii, for example, to sleeve I4 and thence through screw 22 to the connecting strap 2| of the meter. The screws I2 are provided with annular grooves 23 just back of their heads 24, these grooves being provided by the manufacturer of the test blocks, for the reception of the conventional spring clips, used upon the jumpers commonly employed to bridge the meter contacts when testing is to be done.

The parts so far described are of presently known and widely used meter mountings and connections and the practice described of bridging the contacts with jumpers consisting of short sections of cable and conventional spring clips is the practice that has existed for years and is being followed at the present time.

However this practice has become increasingly dangerous due to the fact that the loads carried by the meters have constantly increased. Thus it is common to nd meters carrying loads of amperes, at 220 volts or even more. The contact provided by ordinary, manually squeezeable, clips is not sucient to carry a. load of this character without overheating at the points of engagement of the clips with the screws I 2. It will be 0bserved that the heads of the screws I2 are set back behind the front edges of the fore and aft walls S. This is designedly done by the manufacturer to cause the screw heads 24 to lie in what is, in eiiect, recesses, so that these heads cannot be accidently bridged by any article extending transversely across the block. However this feature which makes for safety under ordinary conditions introduces an element of diliculty when the meter tester seeks to insert the spring clip into this somewhat restricted space. It is clear that. if, after the meter tester had connected one end of the jumper to one ci the screws I4 and was attempting to connect the 4other end to another screw I4, such jumper should slip out of his hand or a second spring Yclip-should slip off of the second screw and fall vagainst the grounded metal box in which the meter is mounted, a heavy short circuit might be created and serious injury to the meter tester might easily result.

While 1the areaof contact between two v.surfaces makingelectrical contact is important, the A iegree of pressure exerted between said surfaces is even more important and with a view to providing a structure which will not only engage the heads of the screws I4 in such .a manner `that they cannot possibly be accidently dislodged, and atthe same time to provide a Structure which the contacting surfaces will be .brought ,into .forcible engagement with each other, I have devised .the device of the invention.

In carrying out the invention I provide a 1h01- low trough-like member 26 the forward end of which has its walls inturned to provide a ange '21, adapted to be slipped into engagement with vthe annular groove `23 of the head of the screw '2f V"TroughZG 'has aflined thereto a nut 28 into -which `a pressure screw 29 is threaded. This is'crew isprovided with an operating knob 30 upon its outer end by which the screw may be rotated in the .fnut and when the screw 29 is screwed up 4"against rthe 4screw I2 the flange 21 of the trough 4'26 is'drawn 4into very forcible engagement with the head 24 of thescrew 12. This not only're- Isultsrin bringing about Va very firm engagement of'fthe coniiectmorwith the Ahead of the screw 12, lbut-it-ir`isur`es a very efiicient electrical connection Abetweenthe connector and screw l2.

` Note vthats-the rflange 21 extends not only along vtwo -sides of the screw -but across the bottom thereof. v'Thus -it engages `with the rear face of -thescew -head 24 through an arc ofconsiderably y'rr'ire than 'fl-80 degrees, whereby an electrical -connection oi large current passing capacity is effected.

`Any desired way may be resorted to Vo f secur- `ingthe -necessary electrical cable to constitute -a `jumper, tothe s leeve'ortrough Y2E. One such wayis tobend the material o f the trough downwardly as 'indicated at el in Fig. 5to thereby produce two slightly separated ,metallic portions adapted -to have bound between 4them by .a bindscrew 1w32`the pared end 33 `ofthecable A3 4 of "the Ajumper. AAlso any suitable means may he employed for so insulating `the connector that it may be grasped by the Vtester for applying it, without dangerof shock. vFor that purpose I Ihave`-indicated an insulating sleeve 35 upon the serew and an additional insulating sleeve Y36 in iFigN'I. However these insulating sleeves consti- -tute-nopart ofthe invention, the invention Vre- V'siriingin the means described for bringingabout asecure and electrically Yeiective connection ,beltween ythe head of the screw I2 andthe trough 126. Therefore, I wish it to be understood that any way may be resorted to of connecting the vjumper cableto these elements.

`While the device of the invention is primarily 4intended for vuse in testing meters it is apparent that it may be employed in other relations, and 'todndicate that this is thecase I have illustrated in Fig. 3 the trough v26 having its anged end 21 engaged behind a screw 28x ofconventional type.

In the modified lform illustrated in Fig. 8 the wire 331i; of jumpercable 34:1: is rigidly afliXed-to a cup-like tip 40 which is slidable ina housing 26a. This housing corresponds t0 housing 2.6 in that its end is provided with the inturned ange 21a corresponding to iiange'Zl which engages behind the head 24 of a screw l2,.or other headedelement, with which itisdesired to `maize electrical contact. The housing is threaded into or otherwise rigidly affixed in the end of a tubular member 4I of insulating material. A second member of insulating material 42 is threaded 111.50 .the rear .end of member# endete forward end thrusts against the -rear end of f tipil.

When the flange 21a is engaged behind head l,24 of screw I 2, by passing the screw head laterally through the open side of the housing at 2Gb, and

the .member 4I is held against turning with the lijhigers lofone,handand the member 42 is screwed into AI; .the pressure created by the screw action Eis transmitted through tip 40 to screw head 24 and Ltl'iis pressure ,is utilized to draw the flange 21a strongly against the rear face of the screw head. Thus it Awill be seen that the structures of .-lfigs. and 8 have the common feature of a flange engaging behind a screw head for more .than half of .the `circumference.of v:said head and .a screw .threaded .part functioning :to A,pull .the flange against the V.rear face of `thescrew, `while securingthe whole rmlyinplace yon thescrew.

It is to be understood that hthe invention -is not limited to the yprecise .construction ,s et forth but 1that it includes .within pnrview `whatever changes fairly come within either 1the vterms-or 'thesp-irit` of ,the `appended claims.

`Having described my invention .what -I ,claim 1s:

1. yelectrical connector =for -connecting an electric cable .to a .headed ,screw .comprising .a tubular housing element having a lateral 4optening adjacent oneend and an inturnedlangeat said en@ an electric cable having a tipslidable in said housing and a two part lmernber. unii'.,e d by screw threads-one LofthelpartsL-leeing ,aixed to the housing and the other of said parts acting under the screw threads to thrustsaid .tip forcibly aeainSt-the'rearrfee OffSaid-.heaa :both ofthe said parts being tor-med of insnlating material.

2,. An electrical connector for cpnnecting an electric cable to a headed binding post, said oonnector 4comprising `two axially aligned members of insulating material having threaded engage.- ment with :each other, whereby turni-ng of .said parts with respect to each other causes one of said aparts, hereinafter .referred to as the Yfirst .part t0 :move -erldwise into the-ctherfandfrsecond part, a housing elementprojcctllg'axiallybeyond .one end :of said second parte d housing. element having end portions shapd .'CD :be Engaged behind .the head of the binding post Joy ,lateral movement of .the housing element with respect to the said post, an electric :cable havinga-.tip .amxed thereto, said cablepassingfreely through said rst part andsad tip being slidablednsaid bearing housing, said tip Abeine of srch gdimensions with reSDsCt-tp the first part that-.theznner .end of the latter 4bears @esel-est -thesaid .tip .to thrust Said tip `fercblvagainst'theheachof:the post and thereby draw :the .end V:nortionsmf y.the housing forcibly against the irear @face .of rthe head Qf saidfnost.

EDXVIN 3A. Y'NOYTES REFERENCES YSCL'EED The following y.references are loef record inv-the le .of ,this :patent:

,UNlTEDSTATES `lSmnber Name V=1Df tte I1,'795562? Wentz et ,a1 -iMar .10.11931 1,198,812 Rosenback .V Mar.;1,.193.1 2,092,6.3l Bakhe etal. lSept 57,1193? 22531432. IOhIlSQe "navega-Aue, 1Q,..1.94l 

